TORONTO – After enduring an intense exercise regime, secretly using performance-enhancing drugs, and immersing himself in the world of Lance Armstrong to portray the cyclist on the big screen, Ben Foster was left with one feeling for the controversial athlete.

“Empathy,” said the actor. “It was a complicated time. He’s a complicated man.”

It’s a feeling Foster hopes audiences can also come away with after watching “The Program,” which tracks Armstrong’s incredible cycling career and the behind-the-scenes doping that drove it.

Armstrong, a cancer survivor and longtime athlete, was once an American sporting hero, but is now a divisive figure.

He has been banned from cycling for life and had his seven Tour de France titles stripped after telling Oprah Winfrey in a 2013 interview that he used performance-enhancing drugs.

Foster knew the bare-bones of Armstrong’s story before making “The Program,” which was directed by British filmmaker Stephen Frears. But playing the athlete made him appreciate the broader culture of doping that existed in cycling at the time.

“He did doping better. He did nutrition better. He did the cycling gear better. He did training better. It’s not about being a liar. If everybody’s doping, everybody’s lying,” Foster said, noting that Armstrong also raised millions for cancer research over the course of his career.

“He treated people in a particular way that I don’t necessarily agree with but the complexity of the good that he did, with the way that he did it, deserves a deeper consideration.”

To properly capture Armstrong’s intensity, Foster — unbeknownst to the rest of his cast, but under the supervision of a doctor — took performance-enhancing drugs himself and only revealed what he had done after filming had wrapped.

He also tried to reach out to Armstrong, but the athlete wasn’t interested in talking.

Foster nonetheless describes himself as a fan of Armstrong’s, saying he found himself defending the cyclist on the set of the film.

“We don’t like that Lance didn’t apologize in a way that felt sincere. And that’s why we’re punishing him still,” he said. “I don’t condone or condemn … I think it’s a complicated story.”

Chris O’Dowd, who plays David Walsh, an Irish journalist who worked to bring Armstrong’s doping into the spotlight, agreed that the cyclist is a complex character and noted that the film attempts to provide a better picture of the intricacies of his world.

“He was an incredible athlete, very manipulative, vindictive, self-centred, very smart, and ego driven,” he said. “I think he’s a fascinating person to watch.”

O’Dowd’s personal feelings about Armstrong, however, tend to waver.

“At times I feel slightly sorry for him. But then I think of how he treated some people … and I think, ‘I don’t know if he needs our sympathy,’” he said. “I think he’s a fallen hero, but still a kind of hero.”

“The Program” opens in Toronto, Calgary, Ottawa, Vancouver and Montreal on Friday.